Accurate ink level sensing in ink supply reservoirs for various types of inkjet printers is desirable for a number of reasons. For example, sensing the correct level of ink and providing a corresponding indication of the amount of ink left in a fluid cartridge allows printer users to prepare to replace depleted ink cartridges. Accurate ink level indications also help to avoid wasting ink, since inaccurate ink level indications often result in the premature replacement of ink cartridges that still contain ink. In addition, printing systems can use ink level sensing to trigger certain actions that help prevent low quality prints that might result from inadequate supply levels.
While there are a number of techniques available for determining the level of fluid in a reservoir, or a fluidic chamber, various challenges remain related to their accuracy and cost.